For a plasma processing apparatus in which various types of plasma processing, such as plasma etching and plasma CVD, are carried out on a semiconductor wafer, it is important to know an ion flux which is one of parameters representing the conditions of plasma, in order to increase stability of processes for producing products or to develop processes for manufacturing products.
As a method of measuring an ion flux, there has been proposed a method including installing a probe high-frequency oscillation unit for causing an oscillation in a plasma processing chamber at an oscillation frequency different from oscillation frequencies of a plasma source power supply and a high-frequency bias power supply, and a high-frequency receiver for receiving the high-frequency wave oscillated from the probe high-frequency oscillation unit by using a surface in contact with plasma; and measuring impedance, reflectivity and transmittance, and a variation of a harmonic component for every oscillation frequency in an electric circuit including the probe high-frequency oscillation unit and the receiver (see Japanese Patent Application Publication No. 2011-014579, for example). In addition, there has been proposed a technique of measuring an ion flux in which a chip-like substrate having a total energy flux measuring unit and a residual ion measuring unit is disposed in a region where a workpiece is to be located in a vacuum treatment space, and an ion flux is measured by a current generated in the measuring units upon incidence of ions. (see Japanese Patent Application Publication No. 2010-232527, for example).
Although there have been proposed various techniques to measure an ion flux including those described above, the present invention presents a novel approach for obtaining an ion flux based on the idea that an ion flux incident on a semiconductor wafer is a type of energy and the ion flux incident on the semiconductor wafer is changed into heat, and thus the ion flux can be obtained by calculating a heat flux in the semiconductor wafer